Houston Chronicle Sunday

World’s waterways turning to dust as heat takes toll

- By Brian K Sullivan

Rivers across the globe are disappeari­ng.

From the United States to Italy to China, waters have receded, leaving nothing but barren banks of silt and oozing, muddied sand. Canals are empty. Reservoirs have turned to dust.

The world is fully in the grip of accelerati­ng climate change, and it has a profound economic impact. Losing waterways means a serious risk to shipping routes, agricultur­e, energy supplies — even drinking water.

Rivers that have been critical to commerce for centuries are now shriveled, threatenin­g the global movement of chemicals, fuel, food and other commoditie­s.

The Rhine — a pillar of the German, Dutch and Swiss economies — has been virtually impassable at times in recent weeks. The Danube, which winds its way 1,800 miles through central Europe to the Black Sea, is gummed up too. Trade on Europe’s rivers and canals contribute about $80 billion to the region’s economy just as a mode of transport.

In China, an extreme summer has taken a toll on Asia’s longest river, the Yangtze. Diminished water levels have hobbled electricit­y generation at many key hydropower plants. Mega cities including Shanghai are turning off lights to curb power use, and Tesla has warned of disruption­s in the supply chain for its local plant. Toyota and Contempora­ry Amperex Technology, the world’s top maker of batteries for electric vehicles, have shuttered factories.

Drought plaguing the Colorado River — a source

of water for 40 million people between Denver and Los Angeles — has gotten so extreme that a second round of drastic water cuts are hitting Arizona, Nevada, and Mexico.

The retreating waters of the U.S. Southwest are exposing bodies, and dinosaur footprints that had

been submerged for perhaps millions of years have been exposed.

The reasons global waterways have dried to a trickle are complex. There’s the impact of the weather-roiling La Niña, prolonged drought in many regions and also simple bad luck. But the biggest driver underpinni­ng the shift is climate change.

“It’s a combinatio­n of many factors leading to this particular­ly extreme event,” said Daniel Swain, a climatolog­ist at the University of California Los Angeles. “But there is clearly a role for climate change, which made multiple underlying, recordbrea­king, and in some cases, record-shattering heat waves dramatical­ly more likely.”

The Earth’s rising temperatur­es have meant mountain ranges are getting less snow, leaving less water to flow down to streams in summer during the melt, said Isla Simpson, a scientist at the National Center for Atmospheri­c Research in Boulder, Colo.

Mountain snow is nature’s reservoir. When snowfalls dwindle, the source of many rivers — from the United States to

China to Europe to the Middle East — vanishes, said Swain of UCLA.

Then there is La Niña, a cooling of the equatorial Pacific Ocean that upsets global weather patterns, bringing heavy rains to some areas and drought to others. The world is in its second straight La Niña, and the odds are rising 2023 will see another one.

“The ongoing and strong La Niña connects the droughts and low river flows in North America, Europe, Middle East and the southern hemisphere,” said Richard Seager, a research professor at Columbia University’s Lamont Doherty Earth Observator­y.

The world’s hotter temperatur­es also mean that waterways are literally evaporatin­g away.

Or as Seager puts it, the warming atmosphere “is sucking more moisture from the land surface.”

 ?? Darko Vojinovic/Associated Press ?? A kayaker paddles by the hulk of a World War II German warship in the Danube River near Prahovo, Serbia. Dozens of battleship­s have been exposed.
Darko Vojinovic/Associated Press A kayaker paddles by the hulk of a World War II German warship in the Danube River near Prahovo, Serbia. Dozens of battleship­s have been exposed.

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